ii8 Mr. Hatchett's Experiments on a Substance , 
acid upon carbonaceous substances. I have since extended 
these experiments, and shall here give some account of them. 
l. 
200 grains of the fresh peels of horse chesnuts were di- 
gested for about 12 hours in three ounces of distilled water. 
The liquor was of a pale brown, and formed a slight pale 
brown precipitate when solution of isinglass was added to it. 
2. 
200 grains of the same peels were moderately roasted, and 
being afterwards digested with three ounces of water, formed 
a dark brown decoction, which was not rendered turbid by 
gelatine. 
3 - 
The above mentioned roasted peels, after the termination 
of the preceding experiment, were added to the remainder of 
the filtrated liquor. A quarter of an ounce of nitric acid was 
poured upon the whole, which was then digested and eva- 
porated to dryness. The mass was afterwards infused in water, 
and a dark reddish-brown liquid was obtained, which copiously 
precipitated solution of isinglass. 
4 - 
200 grains of horse chesnuts, from which the peels em- 
ployed in the former experiments had been taken, were 
bruised, and were digested with three ounces of water. The 
liquor was turbid, and of a pale red colour. It was filtrated, 
and some solution of isinglass was added, but without any 
effect. 
